I was pretty surprised to see that as well. From the NERW piece, it seems like WJJB will end up on 1440 and 96.3, WLOB on 1310 and 96.3, and the WEEI affiliate on 95.9.
The move seems a bit screwy. Given the track record of WEEI's stations in Boston, Providence, Springfield, and Worcester; the affiliate will probably blow WJJB out of the water. It would be a shame to lose WRED as well; though the latest book wasn't too hot to Red Hot 95.9, they usually rank much better than WLOB.
In terms of signals for the FMs, 95.5 is definitely covers the fewest people; while the upgraded 96.3 covers a massive land area, it's the 95.9 stick that probably hits the most people. With 96.3's upgrade throwing a decent signal over the city of Portland (as Andy said, for spoken-word), perhaps that's really where the WEEI format really belongs. To me, the best fit would be leaving things where they are, other than demoting WLOB to 1310 and using the big 96.3 for WEEI. Though the signal to the south isn't the best south of Scarborough, 96.3 provides a strong signal to the colleges full of Boston expatriots in Waterville, Lewiston, and Brunswick - sure, college students don't have diaries, but that's got to be a sellable audience with the WEEI brand.
That being said, that move would really only work if WEEI had no plans for a Portsmouth-area affiliate. If this affilate is expected to cover greater Portland and most of York County, then 95.9 is the only choice. At least that's my $0.02.